Paleomagnetism of Permian-Triassic volcanic sequences from Son La province, northwest Vietnam

Nineteen sites with 198 oriented-core samples have been collected from the Upper Permian-Lower Triassic volcanic rocks of Vien Nam Formation at Quynh Nhai locality, Son La Province, northwestern Vietnam. The characteristic remanent magnetization components carried by magnetite and hematite were successfully isolated from secondary components reveal a mean paleomagnetic direction Ds = 48.3°, Is = -10.0°, a95 = 8.0°, corresponding to a virtual geomagnetic pole located at l = 35.7°N, f = 217.4°E and a paleo-latitude of study area situated at 5.1°S during the Permian time. Compared with the Late Permian-Early Triassic pole of the South China Block (SCB), the data show that crustal elements of NW Vietnam have been close to, but not unequivocally a coherent part of the SCB, since the Late Permian. Development of the parallel NW-SE striking Song Ma and Song Chay orogenic belts did not involve the closure of wide (> 500 km) ocean basins.

Paleomagnetism of Permian-Triassic volcanic sequences from Son La province, northwest Vietnam

Nineteen sites with 198 oriented-core samples have been collected from the Upper Permian-Lower Triassic volcanic rocks of Vien Nam Formation at Quynh Nhai locality, Son La Province, northwestern Vietnam. The characteristic remanent magnetization components carried by magnetite and hematite were successfully isolated from secondary components reveal a mean paleomagnetic direction Ds = 48.3°, Is = -10.0°, a95 = 8.0°, corresponding to a virtual geomagnetic pole located at l = 35.7°N, f = 217.4°E and a paleo-latitude of study area situated at 5.1°S during the Permian time. Compared with the Late Permian-Early Triassic pole of the South China Block (SCB), the data show that crustal elements of NW Vietnam have been close to, but not unequivocally a coherent part of the SCB, since the Late Permian. Development of the parallel NW-SE striking Song Ma and Song Chay orogenic belts did not involve the closure of wide (> 500 km) ocean basins.

Method of the equivalent photons for modulated electron beam

It is shown in this work that electromagnetic self-field of the periodically density modulated electron bunch can be considered as the beam of the equivalent photons (pseudo-photons), collimated along the electron velocity. Pseudo-photon spectrum includes both the incoherent contribution being proportional to number of electrons in the bunch and the coherent part with the sharp maximum corresponding the modulation frequency. Method of the equivalent photons can be applied for description of the interaction between the electron bunch and a crystal that leads to generation of the coherent parametric X-ray radiation by the modulated bunches exited from the undulator of the X-ray free electron laser. It provides the possibility to obtain the X-ray pulses directed at the large angle to the electron velocity where intensity of the background radiation essentially decreased. It is defined the conditions when the spectral and angular distributions of the coherent pseudo-photons can be compared with the analogous values for the pulses of the X-ray laser.

Interplay of Direct and Indirect Charge Transfer Pathways in Donor-Bridge-Acceptor Systems

Charge transfer in donor-bridge-acceptor (DBA) structures typically takes place through the combination of donor-bridge and bridge-acceptor overlap integrals forming an effective, indirect electronic coupling between the donor (D) and acceptor (A) moieties. Here, we examine the effects of an additional direct DA electronic coupling on charge transfer processes in DBA systems with local interaction to thermal baths. First, using the exact Nakajima-Zwanzig master equation (NZME) for the reduced density matrix, we rigorously define probability currents as the coherent part of the NZME, thereby allowing us to quantify the contribution of the different electronic pathways (direct and indirect) to the charge transfer dynamics. Focusing on two minimal DBA systems of three sites (V and L models), and adopting well-developed methods, we find that the interplay between different transfer pathways can be assessed by the McConnell formula in the weak systembath coupling regime. We then demonstrate that the combination of indirect and direct donor-acceptor coupling either enhances or leads to a destructive quantum interference effect on charge transport processes, depending on the energy landscape of the DBA system.<br>

Interplay of Direct and Indirect Charge Transfer Pathways in Donor-Bridge-Acceptor Systems

Charge transfer in donor-bridge-acceptor (DBA) structures typically takes place through the combination of donor-bridge and bridge-acceptor overlap integrals forming an effective, indirect electronic coupling between the donor (D) and acceptor (A) moieties. Here, we examine the effects of an additional direct DA electronic coupling on charge transfer processes in DBA systems with local interaction to thermal baths. First, using the exact Nakajima-Zwanzig master equation (NZME) for the reduced density matrix, we rigorously define probability currents as the coherent part of the NZME, thereby allowing us to quantify the contribution of the different electronic pathways (direct and indirect) to the charge transfer dynamics. Focusing on two minimal DBA systems of three sites (V and L models), and adopting well-developed methods, we find that the interplay between different transfer pathways can be assessed by the McConnell formula in the weak systembath coupling regime. We then demonstrate that the combination of indirect and direct donor-acceptor coupling either enhances or leads to a destructive quantum interference effect on charge transport processes, depending on the energy landscape of the DBA system.<br>

Herodotus’ Book 2 and the Unity of the Work

Charles Fornara was a pioneer in Herodotean studies by showing how deeply the Histories reflected on the political and intellectual conditions of the author’s own time, but he considered Book 2 as an exception, representing an early stage within Herodotus’ development. The aim of this paper is to show that Book 2 can be seen as a coherent part of the Histories as a whole, looking in particular at Herodotus’ geographic conception, the chronological order within his work, the basic elements of his ethnographic principles, and his approaches to a religious history. Eventually, the arrangement of his colourful stories about the Egyptian kings follows a deliberate concept. His analysis lets us see, once again, that Herodotus was fully conscious of the actual political situation of his own time.

Conclusions

This chapter draws out some lessons from the analysis presented in the book. It discusses the implications of shared powers jockeying over public policy for drifts and their outcomes. It illustrates that policy drifts are a rational, coherent part of the dynamics of public policy making. Political uncertainty does not cease once policies drift. A new stimulus for change will arouse interests from relevant stakeholders and new policy drifts will ensue. To the extent that there are no social, political, economic, or ideological forces pushing for change, the most recent drift remains in place. In this sense, some policy drifts may remain more durable than others.

The Interactions of In-Cylinder Flow and Fuel Spray in a Gasoline Direct Injection Engine With Variable Tumble

Particle image velocimetry (PIV) system was used to measure the tumble structure of the in-cylinder airflow in a four-valve optical gasoline direct injection (GDI) engine. The tumble ratio was controlled by a flap in the manifold and a baffle in the intake port. With proper orthogonal decomposition (POD) method, the velocity field was decomposed into four parts, i.e., the mean, coherent, transitional, and turbulent. The effect of tumble motion on the cycle-to-cycle variation (CCV) of airflow and spray was investigated by calculating the shear strain vorticity. The results indicate that the flow structure can be effectively changed through the combination of flap and baffle by forming a single large-scale tumble flow with the tumble ratio three times higher than the original one. According to POD analysis, it is revealed that the large-scale strong tumble motion leads to the energy occupation ratio of the mean part greatly increase by up to 30%, while the energy transferred to the coherent part is reduced. The above process also decreases the CCV of the coherent part by 50%; thus, the CCV of the whole airflow in the cylinder can be suppressed. A single large-scale tumble increases the maximum shear strain rate up to 2400 s−1. Meanwhile, the maximum vorticity increases to about 6000 s−1 by rolling up of the airflow. The contact area between spray droplets and air becomes larger, and the momentum exchanges between them contribute to wider sprays cone angle and shorter penetration distance when the flap is closed. The statistics of the measurements illustrate that a single large-scale tumble can promote the formation of homogeneous mixture and reduce the fluctuation between multicycles.

Mixed finite element for modelling interfaces

A special finite element based on Reissner’s mixed variational principle has been presented to model interface between two materials. The present element is a 7-node two dimensional mixed finite element with 5 displacement nodes and 2 stress nodes. The mixed interface finite element ensures the continuity of stress and displacement vectors at the interface on the coherent part and the discontinuity of this one on the cracked part. This element has been formulated starting from a parent element in a natural plane with an aim of modelling different types of interfaces with various orientations. This work is essentially devoted to the formulation of the interface element and the study of convergence and validation of this element. Results obtained from the present mixed interface element have been shown to be in good agreement with the analytical solutions.